Answer:
C) a fire starts in a forest, then spreads over thousands of acres
Explanation:
In positive feedback, an effect is amplified or enhanced by influencing itself. Usually the event occurs with a result. The result is such that it further amplifies the event resulting in increased production of the result. Hence a positive feedback loop is created where the result keeps on getting magnified.
Since a fire is started in an area in forest and then it spreads to acres as it encounters more and more dry foliage, it is an example of positive feedback. The result which is fire is magnified as more areas come under the fire.
